I'm assuming that by Java, you mean Java Runtime Environment. The only other option is the Java Development Kit and, unless you are a programmer that knows Java, you won't ever need. There are two kinds of Java Runtime Environments. Well, made by two different people. One is Oracle Java. It's hard to install and is proprietary, meaning it has a strict license agreement that restricts your use of it. The other is OpenJDK. It has less bugs, easier to install, and is free and open source software. OpenJDK is clearly the better choice, so I'll help you get set up with the OpenJDK Java Runtime Environment. Open up a terminal again and type in cat /etc/issue and press Enter. This will give you your Ubuntu version. If you get "Ubuntu Trusty Tahr", type the following command: sudo apt-get install openjdk-7-jre icedtea-plugin -y. If you get "Ubuntu Utopic Unicorn", type in sudo apt-get install openjdk-8-jre icedtea-plugin -y. If you get "Ubuntu Precise Pangolin" or something else, update your verison of Ubuntu. When you enter those commands, you will be asked for the super-use rpassword. This is not always your password. For information, contact your system administrator. One last note, the Java plugin you installed (runs Java applets in browser) works in every browser EXCEPT for Google Chrome. Don't worry about it. You probably won't need it.